Tool · Investor Sam Fit

BMR & TDEE Calculator (Harris-Benedict)

June 30, 2026 • By the Investor Sam Editorial Team • Reviewed by Berly Sam Varghese, Editor
Your basal metabolic rate (BMR) is the number of calories your body burns at complete rest just to keep you alive — heartbeat, breathing, brain, and cell repair. Multiply it by an activity factor and you get your total daily energy expenditure (TDEE), the calories you actually burn in a day. This calculator uses the revised Harris-Benedict equation, one of the longest-standing formulas in nutrition science, so you can anchor a cutting or bulking plan to a real number.

Example: Bodyweight: 80 kg · Height: 178 cm · Age: 32 years · Sex: 1 · Activity level: 1.55

Basal metabolic rate (BMR)1,832.68
Total daily energy expenditure (TDEE)2,840.65

Worked example

Take a 32-year-old man weighing 80 kg at 178 cm. The revised Harris-Benedict equation gives 88.362 + (13.397 x 80) + (4.799 x 178) - (5.677 x 32) = about 1,833 calories a day at rest. Multiplying by a moderately active factor of 1.55 yields a TDEE of roughly 2,841 calories, which is the maintenance number he would eat below to lose fat or above to gain.

Frequently asked questions

What is the difference between BMR and TDEE?

BMR is the calories you burn at total rest, doing nothing but staying alive. TDEE adds the energy you spend moving, digesting food, and exercising by multiplying BMR by an activity factor. TDEE is the number you compare your food intake against to gain, lose, or maintain weight.

How accurate is the Harris-Benedict equation?

It is a solid population estimate but can be off by a few hundred calories for any individual, because it does not know your exact body composition. Use it as a starting point, then adjust based on how your weight actually moves over 2 to 3 weeks.

Which activity level should I pick?

Be honest and lean conservative. Most people overestimate. Sedentary fits a desk job with little training, moderate fits 3 to 5 real workouts a week, and the top levels are for people with physically demanding jobs plus training. Picking too high a factor is the most common reason a plan stalls.

Does muscle change my BMR?

Yes. Muscle is more metabolically active than fat, so two people of the same weight can have different BMRs. Equations like this one use weight, height, age, and sex as a proxy, so a very muscular person may burn somewhat more than the estimate suggests.

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Sources

Berly Sam Varghese · Editor, Investor Sam

Berly Sam Varghese is an engineer who treats money the way he treats any hard problem — something to be engineered, not gambled on. He funded years of education and built real financial stability the patient way, by living below his means and investing rather than borrowing. He writes for the person trying to invest in their health without wasting money. He reviews and approves every article on Investor Sam and checks the figures against primary sources before anything is published. More about our standards.